Objective:

The purpose of this study was to investigate the persistence rate and clinical impact of a persisting iatrogenic atrial septal defect (iASD) after interventional left atrial appendage occlusion (LAAO).

Background:

Interventional LAAO is an alternative to oral anticoagulation (OAC) for the prevention of ischemic stroke and systemic embolism in patients with non-valvular atrial fibrillation (AF). Device placement requires puncture of the interatrial septum. Data regarding incidence and persistence of iASD after LAAO procedures and its clinical relevance is scarce.

METHODS:
We retrospectively analyzed 144 patients that underwent LAAO at our center between 2010 and 2020 who underwent routine follow-up including transesophageal echocardiography (TOE) and who had evidence of an iASD. Baseline clinical, procedural data and echocardiographic characteristics including RV function in patients with and without evidence of an iASD were compared. We furthermore determined the rate of iASD persistence and evaluated outcomes of patients with and without spontaneous iASD closure.

RESULTS:

After a median of 92 days (IQR 75-108 days), we identified 50 patients (50/144, 34.7%) with an iASD. Patients with persisting iASD had higher CHADS-VASc-scores (4.9±1.5 vs. 4.2±1.2, p=0.03), larger left atrial volumes (80.5±30.5ml vs. 67.1±19.7ml, p=0.01) and were more likely to have relevant mitral regurgitation (≥II) (46.0% vs. 12.3%, p=0.001). LAAO procedures took longer (50.1±24.3 vs. 41.1±17.8min, p = 0.06) and were more demanding in patients with a persisting iASD. Furthermore, larger device sizes were implanted (24.3±3.4mm vs. 22.1±2.8mm, p=0.03) in patients with a persisting iASD. Of note, the presence of an iASD had no impact on mortality, thromboembolism or RV dysfunction.

Long term follow-up TEE (i.e. ≥ 12 months) of patients with an iASD was available in 80.4% after a median of 383 days (IQR 289-415 days). Spontaneous closure of an iASD was documented in 52.0% (26/50). Hereby, similar risk factors were identified for the persistence of an iASD in follow-up (i.e. mitral regurgitation, age, CHA2DS2-VASc score, LA volume, procedure time).

 CONCLUSIONS:
While the presence of a persisting iASD after LAAo was associated with baseline as well as procedural risk factors, patients with a persisting iASD do not exhibit adverse outcomes. Furthermore, qpproximately, 50% of iASD come to spontaneous closure during long-term follow-up.